Apparatus for taking samples of fluids in relatively soft geological formations



y 1957 B. SCHNEERSOHN 2,799,474

APPARATUS FOR TAKING SAMPLES OF mums m RELATIVELY IONS SOFT GEOLOGICAORMAT Filed June 1955 INVENTOR v BORIS SCHNEERSOHN 38 WWMM 4 H!ATTORNEYS United States Patent APPARATUS FOR TAKING SAMPLES OF FLUIDS,IN RELATIVELY SOFT GEOLOGICAL FORMA- TIONS Boris Schneersohn, Paris,France, assignor to Societe tie Prospection Electrique 'ProcedesSchlumberger, Paris, France, a corporation of France Application June16, 1955, Serial No. 515,812

Claims priority, application France June 18, 1954 Claims. c1. ass- 1.4

'The present invention relates to apparatus for taking samples of earthformations traversed bya bore hole drilled into the earth, and morespecifically to sample taker apparatus that is especially adapted forsecuring samples of fluid contained in relatively soft formations,particularly in sands.

In the copending United States patent application Serial No. 503,540,filed April 25, 1955, for Devices for Taking Samples of Fluids inGeological Formations, there is disclosed formation fluid sample takingapparatus comprising a hollow projectile which is adapted to be firedfrom a gun-type device against the earth formation (bore hole side wall)from which a fluid sample is desired, the projectile being secured tothe gun by means such as flexible cables so that it may be readilywithdrawn from the bore hole. The hollow projectile features a temporaryfrangible closure at its front endwhich is adapted to be torn away onimpact with the formation to provide access for information to provideaccess for formation fluid to a fluid receiving chamber through valvemeans which is adapted to close after the fluid sample has been takenand to remain closed while the projectile is being brought to thesurface of the earth. Apparatus of this character is intendedparticularly for taking samples in relatively hard formations, and forthis purpose it is provided with a relatively blunt forward portionwhich is designed to penetrate only slightly into the formation, whileadhering strongly thereto.

It is an object of the invention to provide sample taking apparatussimilar to that described above but which is of particular utility fortaking samples of fluid in softer formations, particularly in. sandstraversed by the bore hole. In the attainment of this object severalserious difiiculties must be overcome. First, since sands are usuallypartially invaded by the bore hole liquid and it is desired primarily toobtain samples of liquid contained beyond the invaded zone, the sampletaking projectiles must be capable of penetrating the formation to arelatively great lateral depth. Further, the sand comprising theformation tends to be drawn into the projectile with the fluid and thereis a strong likelihood of its obstructing the fluid intake passages inthe projectile. Ordinary screening devices cannot be used effectively tokeep out the sand since sand particles collected on such devices tend toprevent the fluid sample from entering the projectile. 1

Another object of the invention, accordingly, is to provide new andimproved formation fluid sample apparatus for securing samples fromrelatively soft formations in which the above-noted difliculties areovercome in a simple yet highly effective manner.

A further object is to provide new and improved formation fluid sampletaking apparatus embodying means for preventing any substantial amountof formation sand from reaching the fluid intake passage withoutsubstantially preventing access of the formation fluid to the samplereceiving chamber in the device.

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According to the invention, the nose of the sample vide access to theorifices as the projectile nose is forced into the formation. Theclosure means includes sealing elements for the orifices which act toprevent sand from" entering the orifices without effectively interferingwith the penetration of the formation fluid into, the projectile.

For a better understanding ofthe invention, reference is made to thefollowing detailed description of a representative embodyment taken inconjunction with the accompanying drawings, in which:

Fig. l is a view in transverse section through a bore hole drilled intothe earth showing. sample taking apparatus according to: the inventionin position in the well;. Fig. 2 is a view in longitudinal sectionthrough a sample taking projectile comprising part of the apparatusshown in Fig. 1; and a Fig. 3 is a side view of the projectile noseportion illustrating how it is deformed by penetration into the earthformation.

Referring first to Fig. l, a bore hole 10 which usually containsdrilling mud 11 is shown traversing earth formations 12 which maycomprise, for example, sands saturated with fluid (liquid or gas) ofwhich it is desired to takesamplesr Suspended-in the bore hole 10 in theconventional. manner is a conventional sample taker gun 13 having apowder chamber 14 formed therein communicating with a gun barrel 15 inwhich a sample taking projectile 16, according to the invention, is re--ceived. The projectile 16 is secured to the sample taker gun 13 by theusual flexible cables 17 by means of which it may be withdrawn from aformation when the apparatus is raised to the earths surface.

In the interest of simplicity, only a single powder chamber 14 and gunbarrel 15 are shown in Fig. 1. In practice,,however, the sample takinggun 13 is usually provided with a plurality of superimposed gun barrels,each of which contains a sample taking projectile 16.

As shown in Fig. 2, the sample taking projectile 16 comprises a hollow,cylindrical projectile-formed of two parts 18 and 19 threaded to oneanother to facilitate fabrication and assembly. The body has formedtherein a sample receiving chamber 20 which is adapted to receive asample of the formation fluid through a port 21. The port 21 is normallyadapted to be closed by a slide valve 22 having a head member 23provided with an upper surface 24 having a groove 25 in which isreceived a sealing ring 26. The sealing ring 26 is adapted to be pressedagainst the forward wall of the chamber 20 so' as to form a fluid-tightjoint.

The valve head member 23 is provided with a cylindrical skirt portion 27slidably mounted in the port 21 and having a plurality of laterallydirected apertures 28 formed therein. The valve 22 includes an upwardlyextending rod member 29 carrying a piston 30 slidably received in a bore31 formed in a disk-like member 32 secured in an opening 33communicating with the port 21. The disk-likemember 32 is provided withaplurality of longitudinally extending fluid passages 34.

At its forward end, the body portion 19 is provided with a shoulderedportion 35 on which is tightly fitted-a nose member 36, a sealing ring37 being provided to insure a fluid-tight joint. The nose member 36 ismade of a hard and friable material such as Duralumin. According to theinvention, it is provided with a rear conical portion 38 having a basewider than the body portion 19, an intermediate cylindrical portion 39and a front conical portion 40. The two conical portions 38 and 46preferably have the same apex angle, say 90".

Formed in the intermediate portion 39 are a plurality of angularlyspaced laterally directed orifices 41 communicating with an axial bore42 leading to a chamber 43 above'the disk-like member 32. Theintermediate portion 39 has two grooves'44 and 45 formed therein, one atthelevel of-the orifices 41 but preferably lesser in thickness: than thesize of the orifices, and the other located near the base of the conicalportion 40. Sealing rings 46 and 47 are placed in the grooves 44 and 45,respectively, and an annular member 48 is tightly fitted over theintermediate portion 39, av third sealing ring 49 being provided in agroove 50 in the annular member 48 to insure fluid tightness. Theforward portion 51 of the annular member 48 is considerablythinner thanthe rear portion thereof and it snugly engages the sealing ring 47 forreasons to be explained later.

Inoperation, the sample taking gun 13 (Fig. l) is lowered to the desiredlevel in the bore hole and the sample taking projectile 16 is firedagainst the side wall by explosion of the powder charge 14 in the usualmanner. The nose member 36 penetrates relatively deeply into theadjacent formation to the position shown in dotted lines in Fig. 1, forexample, to arelatively short distance from the base of the conicalportion 38. As a result, thecylindrical portion 39 is located in a zonein the formation 12 beyond the portion that has been penetrated by thedrilling mud 11. The resistance encountered by the forward portion 51 ofthe annular member 48 as the nose member 36 penetrates the formationcauses the forward portion 51 to open in the form of an umbrella, asshown in Fig. 3, while the base of the annular member 48 remains pressedagainst the conical portion 38 through the sealing ring 49.

Meanwhile, under the effect of the pressure of the liquid, the sealingring 47 is torn away, while the sealing ring 46 moves slightly to therear but still partially blocks the orifices 41. As a result, as shownby experience, the

sand in the formation practically does not penetrate into the passage42, while the latter is filled with the fluid contained in theformation.

The formation fluid passes from the passage 42 into the chamber 43 whereits strong pressure pushes back the valve 22 which slides, guided by thepiston 30 and the skirt portion 27 until it is brought to rest by a stopmember 52 formed on the body portion 18. In this position of the valve22, the formation fluid passes'freely into the chamber through theorifices 28 until the chamber 20 is completely filled. The rearward movement of the valve 22, which is checked by the stop member 52, creates avacuum in the cavity above the piston 30 so that after the chamber 20 isfilled, the valve 22 closes itself as a result of the pressure exertedin the chamber 43 onthe piston 30.

When the projectile 16 is withdrawn from the formation 12 and enters thebore hole 10, the pressure of the drilling mud 11 continues to beexerted on the piston 30 and the differential effect between thepressure of the drilling mud and the pressure above the piston 30 issufiicient in all cases to keep the valve 22 closed tightly on-its seat,thus preventing any rush of bore hole liquid to the interior of thechamber 20. The projectile 16 i'sthen raised to the surface of the earthwhere the sample'contained' in the chamber 20 is recovered.

The invention thus provides novel and highly effective sample-takingapparatus for securing fluid samples from relatively soft formations,particularly sands. By virtue of the novel projectile nose structuredescribed above,

it is possible to obtain fluid samples from locations beyond the invadedzone without any likelihood of the device being stopped up by sand fromthe formation.

The specific embodiment described herein by way of illustration isobviously susceptible of modification in form and detail Within thespirit of the invention. The invention, therefore, is not to be limitedto the exact structures shown but comprehends all modification thereoffalling within the scope of the appended claims.

I claim:

1. Apparatus for sampling the fluid contents of geological formationsand the like comprising, a hollow tubular projectile adapted to bedriven into a formation, a forwardly tapered nose portion tightly fittedon said projectile and having fluid passage means in the side wallsthereof communicating with the interior of said projectile, frangibleclosure means normally preventing communication between said fluidpassage means and the exterior of said nose portion and adapted to berendered ineffective when said projectile is driven into a formation,and means interposed between said closure means and said fluid passagemeans for keeping solid matter outof said fluid passage means.

2. Apparatus for sampling the fluid contents of geological formationsand the like comprising, a hollow tubular projectile adapted to bedriven into a formation, said projectile being closed at one end andhaving a port at its other end, valve means in said port, a forwardlytapered nose member tightly' fitted on said projectile other end, meansforming fluid passages in the side wall of said nose membercommunicating with said port, frangible closure means normallypreventing communication between said fluid passages and the exterior ofsaid nose member and adapted to be rendered ineffective when saidprojectile is driven into a formation, and means inter posed betweensaid closure means and said fluid passages for keeping'solid matter outof said fluid passages.

3. Apparatus for sampling the fluid contents of geological formationsand the like comprising, a hollow tubular projectile adapted to bedriven into a formation, said projectile being closed at one end andhaving a port at its other end, valve means in said port, a forwardlytapered nose member tightly fitted on said projectile other end, saidnose member including a rear conical portion having a base of greaterwidth than said projectile, a substantially cylindrical intermediateportion and a forward conical portion, means forming fluid passages inthe side wall of said nose member intermediate portion communicatingwith said port, frangible closure means normally preventingcommunication between said fluid passages and the exterior'of said nosemember and adapted to be rendered ineffective when said projectile isdriven into a formation, and means interposed between said closure meansand said fluid passages for keeping solid matter out of said fluidpassages.

4. Apparatus for sampling the fluid contents of geological formationsand the like comprising, a hollow tubular projectile adapted to bedriven into a formation, said projectile being closed at one end andhaving a port at its other end, valve means in said port, a nose membertightly fitted on said projectile other end, said nose member includinga rear conical portion having a base of greater width than saidprojectile, a substantially cylindrical intermediate portion and aforward conical portion, means forming in said nose member intermediateportion a plurality of laterally directed fluid passages communicatingwith said port, a sleeve member tightly fitted on said nose memberintermediate portion and having a frangible forward portion, said sleevemember forward portion normally preventing communication between saidfluid passages and the exterior of said nose member and adapted to be"rendered ineffective when said projectile is driven into a formation,and fluid sealing means cooperating with said sleeve member to formclosure means for said fluid passages.

5. Apparatus for sampling the fluid contents of geological formationsand the like comprising, a hollow tubular projectile adapted to bedriven into a formation, said projectile being closed at one end andhaving a port at its other end, valve means in said port, a nose membertightly fitted on said projectile other end, said nose member includinga rear conical portion having a base of greater width than saidprojectile, a substantially cylindrical intermediate portion and aforward conical portion, means forming in said nose member intermediateportion a plurality of laterally directed fluid passages communicatingwith said port, means forming an annular groove in said nose memberintermedaite portion and traversing the entrances to said fluidpassages, sealing ring means in said groove, a sleeve member tightlyfitted on said nose member intermediate portion, said sleeve memberhaving a relatively thick rear portion over a substantial part of eachfluid passage and extending towards said rear conical portion and athinner forward portion extending towards said front conical portionover said sealing ring means, said sleeve member forward portionnormally preventing communication between said fluid passages and theexterior of said nose member and being adapted to be rendered effectivewhen said projectile is driven into a formation, and means cooperatingwith said sleeve member at locations on opposite sides of said sealingring means for providing fluid tight joints thereat.

References Cited in the file of this patent UNITED STATES PATENTS

1. APPARATUS FOR SAMPLING THE FLUID CONTENTS OF GEOLOGICAL FORMATIONSAND THE LIKE COMPRISING, A HOLLOW TUBULAR PROJECTILE ADAPTED TO BEDRIVEN INTO A FORMATION, A FORWARDLY TAPERED NOSE PORTION TIGHTLY FITTEDON SAID PROJECTILE AND HAVING FLUID PASSAGE MEANS IN THE SIDE WALLSTHEREOF COMMUNICATING WITH THE INTERIOR OF SAID PROJECTILE, FRANGIBLECLOSURE MEANS NORMALLY PREVENTING COMMUNICATION BETWEEN SAID FLUIDPASSAGE MEANS AND THE EXTERIOR OF SAID NOSE PORTION AND ADAPTED TO BERENDERED INEFFECTIVE WHEN SAID PROJECTILE IS DRIVEN INTO A FORMATION ANDMEANS INTERPOSED BETWEEN SAID CLOSURE MEANS AND SAID FLUID PASSAGE MEANSFOR KEEPING SOLID MATTER OUT OF SAID FLUID PASSAGE MEANS.